BLEU_sentence.py

from nltk.translate.bleu_score import sentence_bleu
import argparse

def argparser():
    Argparser = argparse.ArgumentParser()
    Argparser.add_argument('--reference', type=str, default='summaries.txt', help='Reference File')
    Argparser.add_argument('--candidate', type=str, default='candidates.txt', help='Candidate file')

    args = Argparser.parse_args()
    return args

args = argparser()

reference = open(args.reference, 'r').readlines()
candidate = open(args.candidate, 'r').readlines()

print(reference)
print(len(reference))
print(len(candidate))

#if len(reference) != len(candidate):
#    raise ValueError('The number of sentences in both files do not match.')

score = 0.

for i in range(len(reference)):
    score += sentence_bleu([reference[i].strip().split()], candidate[i].strip().split())

score /= len(reference)
print("The bleu score is: "+str(score))